//定义一个函数，输入一个链表的头节点，反转该链表并输出反转后链表的头节点。 
//
// 
//
// 示例: 
//
// 输入: 1->2->3->4->5->NULL
//输出: 5->4->3->2->1->NULL 
//
// 
//
// 限制： 
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// 0 <= 节点个数 <= 5000 
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// 
//
// 注意：本题与主站 206 题相同：https://leetcode-cn.com/problems/reverse-linked-list/ 
// Related Topics 链表 
// 👍 93 👎 0

  
package com.yun.leetcode.editor.cn;

public class FanZhuanLianBiaoLcof {
    public static void main(String[] args) {
        Solution solution = new FanZhuanLianBiaoLcof().new Solution();
        ListNode head = new ListNode(1);
        ListNode head2 = new ListNode(2);
        ListNode head3 = new ListNode(3);
        ListNode head4 = new ListNode(4);
        ListNode head5 = new ListNode(5);
        ListNode head6 = new ListNode(6);
        head.next = head2;
        head2.next = head3;
        head3.next = head4;
        head4.next = head5;
        head5.next = head6;
        System.out.println(solution.reverseList(head));
    }
//leetcode submit region begin(Prohibit modification and deletion)
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode reverseList(ListNode head) {
        ListNode next;
        ListNode prev = null;
        ListNode cur = head;

        while (cur != null) {
            next= cur.next;
            cur.next = prev;
            prev = cur;
            cur  = next;
        }
        return prev;
    }
}
//leetcode submit region end(Prohibit modification and deletion)

}